If there's a free program in Dressage on Monday, Germany will not take part, and so will probably many other countries, including the hosts: https://www.reiterrevue.de/news/sport/die-chaos-spiele-gehen-weiter-auch-fuer-die-dressur-9798184.html
The article is in German, but here's the summary:
European teams have booked their flights back to Europe on Monday. They don't want to risk having their horses go to a difficult competition first. According to this, the federations proposed a few days ago to have the final competition take place in a hall on Sunday. But the organizers weren't interested enough and now it's too late. According to the article, most federations have complete understanding for the German decision and/or plan to do the same. The Brits won't take part either. And the US federation agrees as well and plans to withdraw their horses out of solidarity.
Tomorrow, the federations will propose to cancel the planned free program.